ML20059B741
| ML20059B741 | |
| Person / Time | |
|---|---|
| Issue date: | 08/20/1990 |
| From: | Taylor J NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO) |
| To: | Beckjord E, Murley T Office of Nuclear Reactor Regulation, NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES) |
| References | |
| NUDOCS 9008300046 | |
| Download: ML20059B741 (4) | |
Text
3 AUG t 01990 MEMORANDUM FOR:
Thomas E. Murley, Director Office of Nuclear Reactor Regulation Eric S. Beckjord, Director Office of Nuclear Regulatory Research FROM:
James M. Taylor Executive Director for Operations
SUBJECT:
NUBARG BACKFITTING APPEAL ON THE USE OF NUCLEAR HEAT FOR BWR HYDROSTATIC TESTING At its 177th meeting the Committee to Review Generic Requirements (CRGR) recommended several staff actions to me in connection with the subject backfitting appeal. The recommended actions are described in the enclosed copy of Enclosure 2 to the minutes of CRGR Meeting No. 177.
Item 2(a) recommended that RES prepare an amendment to 10CFR50.55a, as well as to Appendix G to 10CFR Part 50, to eliminate ambiguities and inconsistencies in the applicable generic legal requirements.
Item 2(b) recommended that NRR prepare guidance for use by NRC inspectors and technical reviewers to clarify staff intent with regard to specific nuclear hydrotest practices.
Item 2(c) recommended that NRR revise the BWR standard technical specifications to indicate that, when it is necessary to conduct a hydrotest above 200*F in order to satisfy brittic fracture concerns, the test may be performed before installation of the containment vessel head in order to achieve a better inspection.
I agree with the CRGR recommendations and request that you implement them.
Please advise me of your plans and schedules for implementing items 2(a) through 2(c).
If you disagree with any of the CRGR recommendations please indicate the disagreement and describe your alternative recommendation in the response.
Original Signed By:
James M. Taylor James M. Taylor Executive Director for Operations
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E. Jordan
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) to the Minutes of CRGR Meeting No. 177 NUBARG Backfitting Apseal on the Use of Nuclear Heat for BWR
'tydrostatic Testing January 10, 1990 TOPIC The Committee continued its review of the NUBARG backfitting appeal on the use of nuclear heat for hydrostatic testing in BWRs.
The Committee had previously reviewed this matter at Meetings 172, 174 and 175 and had provided the EDO with a recommended response to the NUBARG appeal.
At this meeting the Committee developed additional recommendations for the EDO in areas not explicitly i
addressed in the recommended response to NUBARG.
BACKGROUND 1.
The Committee's recommended response to NUBARG was transmitted by a memorandum dated January 2, 1990 from E. Jordan to J. Taylor.
2.
The Committee considered further in this meeting questions / issues that i
were raised in the course of the discussions at previous meetings of the NUBARG nuclear hydrotest appeal but were not addressed explicitly in the recommended response to NUBARG referred to in (1) above.
CONCLUSIONS /RECOMENDATIONS As a result of the discussions at this meeting of the residual nuclear hydro-test topics identified in the attachment, the Comittee made the following recomendations to complete NRC action on the NUBARG appeal:
1.
The final response to NUBARG issued by the EDO should be released publicly l-in accordance with normal procedures (special distribution to licensees l_
by separate generic communication is not recommended).
l 2.
The recommended EDO response to the NUBARG appeal (Background Item 1.
above) acknowledged ambiguities and apparent inconsistencies in regula-tions and associated guidac.ce documents pertinent to the nuclear hydrotest issue, and indicated that these would be clarified by the staff.
In that regard:
a.
The CRGR recomended that RES prepaia an amendment to 10 CFR 50.55a, as well as to Appendix G to 10 CFR Part 50, to eliminate ambiguities and inconsistencies in the applicable generic legal requirements, b.
The CRGR recomended that NRR prepare guidance for use by NRC inspectors and technical reviewers to clarify staff intent with regard to specific nuclear hydrotest practices.
The principal points to be addressed in preparing this guidance are:
1
2-i.
Use of nuclear heat for verification of repairs done to correct leakage found during required hydrotests.
(Some licensees, although they do not use nuclear heat for the initial hydrotesting required following an outage, apparently do verify during normal power ascension the leak tightness of repairs done to correct leakage found during that initial hydrotest.)
11.
Inclusion of a non-condensible gas bubble in the reactor coolant system during required hydrotesting.
(Some licensees apparently do not vent the reactor vessel head area following installation of.the head during refueling or other major outages, leading to a compressed non condensible gas bubble during required hydrotests.
Although the CRGR had no safety concern with this practice, depending on the size of such a bubble, this could be viewed as a conflict with the staff's intent that hydrotesting should be done water-solid.)
iii. Criticality of the reactor core prior to or during hydrotesting.
(The question of prohibiting core criticality prior to or during hydrotesting was left unresolved in the discussion of this nuclear hydrotest practice at this meeting.
One view expressed was that, conservatively, core criticality should be prohibited until after successful completion of hydrotesting that demonstrated the integrity of the reactor coolant boundary.
Another view was that such a prohibition might unnecessarily preclude flexibility in plant operations that could be benefi-cial to safety in some circumstances; if such practice is to be prohibited, therefore, there should first be a review to deter-mine if any beneficial practices would be precluded.
This matter should be given further consideration in connection with recom-mended rulemaking activities referred to in 2.a. above.)
It was noted during the discussion ~s that, although the staff did not believe any licensees were using nuclear heat to conduct hydrostatic testing, a complete survey to ensure that this was the case had not been conducted.
Publication of the guidance to inspectors and reviewers should obviate any need to do so, c.
The CRGR recommended that NRR revise the BWR standard technical specifications to indicate that, when it is necessary to conduct a hydrostatic test slightly above 200'F in order to satisfy brittle fracture requirements, the test may be performed before installation of the containment vessel head in order to achieve a better inspection.
(Several specific plant technical specifications already have this provision.) The " Bases" for the proposed standard technical specifications should emphasize the central importance of obtaining a good inspection during hydrotests and consider any added risk to the public due to the testing.
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.3 It was noted that NRR was in the process of checking to see if there were any technical specifications which might allow critical i
operation at low temperature with the containment vessel head I
removed.
If so, the issue would be investigated further to determine whether the technical specifications should be revised to prohibit j
crftical operation of low temperature with the containment vessel head removed.
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